1. Field of the Invention
The present invention relates to a thermal transfer recording material and a thermal transfer recording method containing a specific colorant.
2. Description of Related Art
A thermal transfer recording has advantages such as easy operation and maintenance, downsized apparatus, potential reduction in cost and inexpensive running cost. For the purpose of improving stability, particularly fixable property and light resistance of an image obtained by the thermal transfer recording, thermal transfer recording materials and methods for the image formation using thermally diffusible colorants (referred to as chelate colorants) capable of being chelated have been proposed, and described in JP SHO 59-78893A, JP SHO 59-10349A and JP SHO 60-2398A. The chelate colorants disclosed therein are metal chelate colorants formed by bidentate or tridentate coordination of an azo colorant as a ligand to metal ion. An image formed using these chelate colorants is excellent in light resistance and fixable property, but is not sufficiently satisfied in sensitivity and color tone of the thermal transfer recording material, and further improvement has been desired.
Many pyrazolone colorants have been synthesized, their usefulness has been identified, and they have been widely used. Recently, they have been frequently applied to various uses such as photographic photosensitive materials, thermal transfer recording materials, color toner, optical recording media and color filters.
In most pyrazolone colorants in earlier development, a phenyl group is substituted on a nitrogen atom at position 1 of pyrazolone (see U.S. Pat. Nos. 2,265,908, 2,369,355, 2,398,999, 2,409,189, 2,430,558 and 2,519,001). In U.S. Pat. No. 4,757,046, a compound where a methyl group is substituted on the nitrogen atom at position 1 of pyrazolone has been described. However, such pyrazolone colorants have poor solubility in a solvent and low sensitivity, and are inferior in light resistance when used as the thermal transfer recording material.